Muffler



Feb. 9, 1932. HQYT 1,844,855

MUFFLER Filed June 2, 1950 FIG. 1.

20 A; B A 8 FIG. 2 20 INVENTOR.

Ashbel BYJMIWW ATTORNEYS.

Patented Feb. 9, 1932 PATENT OFFICE ASHBEL H. HOY'I', 0F WARE, MASSACHUSETTS I Application fled June 8, 1980. Serial In; 458,867.

The resent invention relates to mufllers primari y intended for use in silencing or deadening the exhaust explosions of internal combustion engines.

The primary object of the invention is to provide a mu er for internal combustion en gines which will effectively reduce the violence of the exhaust gases as they are discharged into the atmosphere, thereby deadening or silencing the explosions and in a manner so as to not create a back pressure in the engine.

A further object of the invention is to provide a mufiler of novel construction wherein the gases entering an expansion chamber of novel construction are permitted to escape thru a series of expansion tubesbefore amlzltually being discharged into the atmosp ere.

Other objects and advantages of the invention will be apparent during the course of the following detailed description, taken in connection with the accompanying drawings forming a part of this specification and in which drawings:

Figure 1 is a central longitudinal section thru the improved mufiler.

Figure 2 is a view showing the inner member in elevation and the outer tube or shell in longitudinal section.

Figures 3 and 4 are rear and front end views respectively of the improved mufller.

In the drawings, and wherein similar reference characters designate corresponding parts thruout the several views, the mufller comprises an inner shell or section A and an outer section or casing B supported axially about the section A.

' The inner section A comprises a rearwardly tapering shell 5 preferably formed from two complementary sections divided longitudinally of the inner section and being closed at its smaller rear end by a preferably flat end wall 6. The front, larger end of the tapering shell is formed with a tubular coupling sleeve 7 arranged axially of the shell and adapted for attachment to the rear end of an internal combustion engine exhaust pipe in any preferred manner whereby the exhaust gases will be discharged longitudinall into the shell. The shell is preferably ma e of metal of like thickness thruout and is formed with a series of frusto-conical portions 8 which gradually decrease in size from the open front end toward the closed end wall 6. These frusto-conical portions 8 taper toward the open end of the shell with the front smaller end of the portions joined with the rear larger end of the adjacent frustoconical portion by annular tapering portions 9 having tapers greater than that of the frusto-conical portions 8 and forming a series of rearwardly directed annular shoulders 10.

The shell portions 8 and 9 provide a circumferentially grooved or corrugated shell forming a series of expansion chambers 11 of decreasing volume from the front to the rear end of the shell.

Each half section of the tapering shell is provided with apertured coupling cars 12 which may be arranged one adjacent each end of the shell sections and one substantially midway the ends for receiving coupling bolts or other suitable fastening elements 13.

Provided in circumferential rows about the shell 5 and opening thru the tapering portions 9 is a series of preferably circular apertures 14 the combined areas of which will be greater than the area of the opening thru the coupling sleeve 7. These apertures 14 are arran ed in staggered relation longitudinally of the shell and each is intended to receive the smaller and of a funnel-shaped expansion tube 15. The flat end wall 6 is also rovided with a number of the apertures 14 or receiving a number of the funnelshaped expansion tubes 15. Each annular row of expansion tubes 15 as will be observed have their axes extending in forwardly converging relation, while the annular series of tubes 15 also have their axes extending in forwardly converging relation. As will be observed, these tubes 15 and 15 are arranged to direct the exhaust gases radially and rearwardly with respect to the shell 5.

The outer section B is in the form of a plain tubular casing being open at both ends to permit free passage of air thru the casing about the shell 5.

The inner section A is supported axially within the outer section B by means of suitable brackets 20 which may be attached to the coupling cars 12 by the fastening elements 13 serving to couple the shell sections together. The outer ends of the brackets 20 may be secured in any preferred manner to the tubular casing B. The section A is mounted in the section B with the expansion tubes 15 spaced from the inner surface of the outer section whereby the gases may readily escape from the tubes and be directed in a rearward direction against the inner surface of the section A. The outer section or tubular casing is of greater length than the inner section and has its rear end projected a suitable distance beyond the rear end of the inner section whereby the gas escaping from the rearmost tubes 15 and the end tubes 15 will be directed against the outer casing.

As will be observed in Figure 2, the expansion tubes 15 are arranged in staggered relation longitudinally of the shell.

In operation, the exhaust gases entering thru the coupling sleeve 7 into the larger end of' the shell will be permitted to expand in the shell and further expansion is permitted when being discharged thru the apertures 14 and 14: having a combined area greater than the intake opening at the front end of the shell. The gas escaping rearwardly thru the tubes 15 and 15 will create a suction rearwardlv thru the tubular casing B and this cold air aside from cooling the gases will also act to cool the expansion tubes. The cold air being drawn into the front end of the casing will also serve to materially cool the shell 5 so that the gas in the shell will be cooled to quite some extent before escape thru the tubes. Byhaving the total area of the apertures 14 greater than the opening thru the front end of the shell back pressure upon the engine will be prevented.

Changes in detail may be made to the form of invention herein shown and described. without departing from the spirit of the invention or the scope of the following claims.

I claim:

1. A muflier comprising a tapering shell. having an inlet opening at its larger end and a wall closing its smaller end, said shell being formed with a series of connected frusto-conical portions providing a series of expansion chambers of decreasing volume from the front to the rear end of the shell, and a series of funnel-shaped expansion tubes having their smaller ends communicating with each of the expansion chambers.

2. A mufiler comprising a tapering shell having an-inlet opening at its larger end and a wall closing its smaller end, said shell being formed with a series of connected frusto conical portions providing a series of expansion chambers of decreasing volume from the front to the rear end of the shell, an annular series of rearwardly directed funnel-shaped expansion tubes communicating with each expansion chamber, and a tubular casing supported concentrically about the shell.

3. A mufller comprising a tapering shell having an inlet opening at its larger end and a wall closing its smaller end, said shell being formed with a series of connected frusto-conical portions providing a series of expansion chambers of decreasing volume from the front to the rear end of the shell, an annular series of radially and readwardly directed funnelshaped expansion tubes communicating with each expansion chamber, and a tubular casing supported concentrically about the shell.

4. A mufiier comprising a tapering shell having an inlet opening at its larger end and a wall closing its smaller end, said shell being formed with a series of connected frustoconical portions providing a series of expansion chambers of decreasing volume from the front to the rear end of the shell, an annular series of radially and rearwardly directed funnel-shaped expansion tubes communicating with each expansion chamber and a tubular casing supported concentrically about the shell and having its rear end extending beyond the rear end of the shell.

5. A mufiler comprising an inner section embodying a series of connected frusto-conical portions of decreasing volume toward the rear end of the shell, an end wall closing the rear end of the shell, a coupling sleeve providing an openinginto the front end of the shell, outlet apertures provided in the connecting sections for the frusto-conical portions and also in the rear end wall, rearwardly and radially directed funnel-shaped expansion tubes connected to the shell at each of said apertures, an outer tubular casing encircling the inner section, and means supporting the inner section axially within the outer casing.

6. A muflier including a shell formed with rearwardly flaring frusto-conical portions of increasing volume toward the forward end of the shell and connected by annular tapering portions providing rearwardly facing annular shoulders, a wall closing the rear end of the shell and a coupling sleeve formin an inlet opening at the front larger end 0 the shell, an annular series of apertures provided in each annular shoulder and in the rear end wall, a series of radially and rearwardly directed funnel-shaped expansion tubes communicating at their smaller ends with each annular series of apertures, an outer tubular casing, and brackets supporting the casing concentrically about the shell and projecting eyond the rear end thereof.

7. A muiiler comprising an inner section including a longitudinally separable tapering shell provided with a series of rearward- 1y facing annular shoulders, an end wall closing the rear end of the shell, :1 coupling sleeve opening into the larger end of the shell and apertured coupling ears provided on each shell section, an annular series of apertures 5 provided in each annular shoulder in staggered relation longitudinally of the shell and an annular series of openings in said rear end wall, a funnel-shaped expansion tube communicating with each of said apertures, 1 said tubes being radially and rearwardly directed from the shell, an outer tubular casing enclosing the inner section, and brackets connected between the apertured coupling ears and said casing for supporting the shell axially within the casing.

ASHBEL H. HOYT. 

